The Dutchman has welcomed two new faces so far, though left-back Luke Shaw and midfielder Ander Herrera were both identified by his predecessor David Moyes.

But although United are interested in both central midfielders and centre-backs, manager Van Gaal said he may opt to persevere with the players he inherited.

"We still have a month to go [in the transfer window] and we are winning. Maybe we don't need other players," Van Gaal said at a news conference at the Michigan Stadium, where his side will face Real Madrid on Saturday.

"First I want to see the players who I have and give them an honest chance."

Chile midfielder Arturo Vidal is one target but Juventus have said that the 27-year-old is keen to stay in Turin.

But Arsenal manager Arsene Wenger has admitted that captain Thomas Vermaelen, another who interests Van Gaal, could leave the Emirates Stadium.

United have lost five footballers this summer with assistant manager Ryan Giggs retiring as a player, Rio Ferdinand and Nemanja Vidic leaving on free transfers and Alexander Buttner and Patrice Evra being sold.

It has left Van Gaal with only three senior centre-backs and one of those, Chris Smalling, will miss the match against Real Madrid.